This invention relates to the field of supporting structures to support operational devices such as exercise equipment, for example to support an exercise bar; toys, for example to support a swing or teeter-totter; and the like. In particular, it relates to a supporting member which can be readily mounted in a doorway between the door jambs for use indoors and just as readily removed therefrom with no damage thereto as a result of such use.
Prior art devices in this field which are known to the inventors include those disclosed in the following United States patents:
U.S. Pat. No. 4,529,191 discloses a bar assembly for an open doorway, having contoured ends to clamp around the opposite upright members of the door jamb, a pair of wedge members screwed into the inwardly facing surfaces of such upright members, a pair of link members connected to the contoured ends of the bar assembly which are wedged into the pair of screwed-in wedge members, the bar assembly having a pair of outwardly projecting arms at each side extending from the contoured ends to the lateral cross bar, such outwardly projecting arms providing leverage when the cross bar is grasped and pulled downwardly causing the contoured ends to clamp the upright members tightly, which together with the wedged link members help to keep the bar assembly from moving downwardly within the open doorway when downward pressure is applied to the lateral cross bar.
U.S. Pat. No. 4,478,409 discloses a hanging chair suspended from mounting brackets secured to the side walls of a pair of spaced apart uprights, such as the uprights of a door jamb.
U.S. Pat. No. 4,364,558 discloses a punching bag apparatus supported on a laterally extending member secured to brackets installed on the spaced apart uprights of a door frame.
U.S. Pat. No. 4,077,403 discloses a telescoping cross bar extending across an open doorway, its opposite ends being supported by doorway riser tubes positioned adjacent the spaced apart upright members of a door frame.
U.S. Pat. No. 2,943,669 discloses a riding toy which can be mounted at the swinging outer edge of a door, by strap members secured to the door knob, spaced apart channel plates to receive the outer edge of the door therein, and a wedge member to wedge between such channel plates and the door to hold the toy more firmly in place on the outer swinging edge of the door.
U.S. Pat. No. 2,839,299 discloses a convertible toy which can be converted from a teeter-totter to a slide, and a cross bar held in an open doorway between the two upright members of a door frame by a pair of circular collars having a planar outer surface pressing against flat plates of soft rubber to sandwich between the collars and the upright members. There is no provision for receiving the vertical abutment strips against which the door abuts when in its closed position by the pair of circular collars, or by the flat plates of soft rubber, nor any structure that would enable them to extend on both opposite sides of such vertical abutment strips to bear against both opposite sides of each of the pair of spaced apart upright members.
U.S. Pat. No. 1,586,899 discloses a see-saw and mounting brackets to clamp on one of the upright members of a door frame.
U.S. Pat. No. 1,401,476 discloses a gymnastic apparatus comprising a one piece bar member extending between two upright members, which can be a door frame, a window frame, two parallel walls or the like, the one piece bar member having rods extending outwardly from each end to seat in respective ones of a pair of blocks, one of the rods being threaded to seat in a correspondingly threaded plate secured to one of the blocks. When rotated in one direction the threaded rod moves the blocks against their respective upright members. The blocks have resilient pads of rubber or felt on their outwardly facing surfaces to bear against the uprights. The blocks do not have any provision to receive the abutment strips of a doorway frame which extend vertically alongside each upright for the door to abut against when in its closed position.
U.S. Pat. No. 1,126,857 discloses a portable gymnastic apparatus comprising a cross bar in one embodiment and hand grips in another embodiment suspended between an open doorway by hook and clamp members secured to the upper cross beam of the door frame.
U.S. Pat. No. 250,738 discloses a portable gymnastic apparatus which includes a cross bar for mounting between the upright members of a door frame, and brackets screwed into or bolted to such uprights to receive and hold the ends of the cross bar.
The supporting bar assembly in accordance with the present invention is an improvement over those of the prior art. Among other things, it includes a pair of pressure plate members rotatably mounted at the outer ends of the bar members for frictional bearing engagement against the upright members of a door frame which include a receiving channel to receive the vertical abutment strips which extend along and project out from each of the upright members for the door to abut against when swung to its closed position. This structure enables the bearing surface of the pressure plate members to extend on both sides of such abutment strips, thereby providing a frictional bearing surface across the entire width of each of the upright frame members for greater frictional holding power. The receiving channel of each pressure plate member also has a planar bearing surface to itself bear against the abutment strip when received therein to provide still additional friction holding power. The side walls of the receiving channel furthermore are in sliding frictional engagement with the corresponding side walls of the abutment strips for even more frictional holding power, as well as to hold each of the pressure plate members and bar assembly itself from forward and backward movement relative to the upright members of the door frame. Thus, when someone is using an item suspended from the bar assembly which pulls forwardly of the open doorway in which the bar assembly is secured, or which pulls rearwardly thereof, the pressure plate members cannot be inadvertently pulled out of position forwardly or rearwardly since their receiving channels each have a corresponding one of the upright abutment strips held therein to prevent any such inadvertent movement out of position.
The pressure plate members of the bar assembly in accordance with this invention also include triangular reinforcing ribs, or gussets, to reinforce the bearing surfaces of the pressure plate members and prevent them from flexing or otherwise being distorted out of their full bearing engagement when great forces are applied to the cross bar members.
The bearing surfaces in accordance with this invention have friction enhancing material rigidly affixed thereto, such as relatively hard rubber or the like, which cannot tend to slip or "bunch up" as soft rubber and other non-rigid materials tend to do when very great sliding forces are applied to a friction bearing surface.
The supporting bar assembly in accordance with the present invention is uniquely adapted for use with operating items which require very great holding power of the cross bar members, such as exercise equipment for use by fully developed athletes having great physical strength as well as for use with playground type equipment such as gliders, swings and teeter-totters which can safely be used not only by very small children but by children of any age.
Further advantages of the supporting bar assembly and operating items in accordance with this invention will become apparent from the detailed description which follows.